package loader

import (
	"context"
	"fmt"

	types "git.kapelle.org/niklas/s3browser/internal/types"
	"github.com/graph-gophers/dataloader"
	"github.com/minio/minio-go/v7"
	log "github.com/sirupsen/logrus"
)

// listObjectsBatch batch func for calling s3.ListObjects()
func listObjectsBatch(c context.Context, k dataloader.Keys) []*dataloader.Result {
	var results []*dataloader.Result

	s3Client, ok := c.Value("s3Client").(*minio.Client)

	if !ok {
		return handleLoaderError(k, fmt.Errorf("Failed to get s3Client from context"))
	}

	for _, v := range k {
		id := v.Raw().(types.ID)
		results = append(results, &dataloader.Result{
			Data:  listObjects(s3Client, id, false),
			Error: nil,
		})
	}

	return results
}

// listObjectsRecursiveBatch just like listObjectsBatch but with recursive set to true
func listObjectsRecursiveBatch(c context.Context, k dataloader.Keys) []*dataloader.Result {
	var results []*dataloader.Result

	s3Client, ok := c.Value("s3Client").(*minio.Client)

	if !ok {
		return handleLoaderError(k, fmt.Errorf("Failed to get s3Client from context"))
	}

	for _, v := range k {
		id := v.Raw().(types.ID)
		results = append(results, &dataloader.Result{
			Data:  listObjects(s3Client, id, true),
			Error: nil,
		})
	}

	return results
}

// listObjects helper func for listObjectsBatch
func listObjects(s3Client *minio.Client, id types.ID, recursive bool) []minio.ObjectInfo {
	log.Debug("S3 'ListObjects': ", id)
	objectCh := s3Client.ListObjects(context.Background(), id.Bucket, minio.ListObjectsOptions{
		Prefix:    id.Key,
		Recursive: recursive,
	})

	result := make([]minio.ObjectInfo, 0)
	for obj := range objectCh {
		result = append(result, obj)
	}

	return result
}

func listBucketsBatch(c context.Context, k dataloader.Keys) []*dataloader.Result {
	var results []*dataloader.Result

	s3Client, ok := c.Value("s3Client").(*minio.Client)

	if !ok {
		return handleLoaderError(k, fmt.Errorf("Failed to get s3Client from context"))
	}

	log.Debug("S3 'ListBuckets'")
	buckets, err := s3Client.ListBuckets(c)

	if err != nil {
		return handleLoaderError(k, err)
	}

	result := &dataloader.Result{
		Data:  buckets,
		Error: nil,
	}

	for range k {
		results = append(results, result)
	}

	return results
}

func statObjectBatch(ctx context.Context, k dataloader.Keys) []*dataloader.Result {
	log.Debug("statObjectBatch")

	var results []*dataloader.Result
	s3Client, ok := ctx.Value("s3Client").(*minio.Client)

	if !ok {
		return handleLoaderError(k, fmt.Errorf("Failed to get s3Client from context"))
	}

	for _, v := range k {
		id := v.Raw().(types.ID)
		log.Debug("S3 'StatObject': ", id)
		stat, err := s3Client.StatObject(ctx, id.Bucket, id.Key, minio.GetObjectOptions{})
		results = append(results, &dataloader.Result{
			Data:  stat,
			Error: err,
		})
	}

	return results
}

// handleLoaderError helper func when the whole batch failed
func handleLoaderError(k dataloader.Keys, err error) []*dataloader.Result {
	log.Error(err.Error())
	var results []*dataloader.Result
	for range k {
		results = append(results, &dataloader.Result{
			Data:  nil,
			Error: err,
		})
	}

	return results
}